Plant anticancer agents X. Isolation of camptothecin and 9-methoxycamptothecin from Ervatamia heyneana.

: The anticancer activity of the roots of Ervatamia heyneana (Apocynaceae) was found to be due principally to the known alkaloid, camptothecin (1). The closely related, but less active, 9-methoxycamptothecin (2) was also obtained. This is the first reported isolation of these biogenetically interesting alkaloids from the indole alkaloid rich Apocynaceae.